It's not just noise reduction but the sharpening of the photos is really crazy. I took a picture of my carpet and it looks nothing like it does in person or up close. Like my carpet is just fuzzy and bland colored, not deep grand canyon crevasses with lots of contrast that show in the iPhone photo.
Cameras don't know how much brightness or contrast something is supposed to have; if you take a picture with only the carpet in frame, on auto AWB and everything else, it's going to be an overly contrasty picture lit as if it's the noontime sun.
That's when you have to switch to something with manual controls.
